The broad objective of this Bioengineering Research Grant is to study biomechanical interactions of angiogenic microvessels with the extracellular matrix (ECM) on the microscale level to develop a computational model of angiogenesis. Our previous work has lead to the hypothesis that the ECM structure adjacent to angiogenic microvessels and the mechanical loading conditions are potential determinants of angiogenic sprouting and neovessel growth and guidance. To test this hypothesis, we will evaluate angiogenesis in a collagen gel-based, 3- dimensional organ culture system of microvessels in the presence of altered mechanical boundary conditions and perturbed collagen fibril structure and gel properties. The interaction dynamics between the angiogenic sprouts and neovessels that form in this culture system with the adjacent collagen matrix and the overall tissue construct behavior will be modeled and analyzed using material point method (MPM). Experimental data of both microvessel behavior and collagen structure dynamics, gathered with advanced imaging techniques, will provide the framework and parameters for the modeling effort. Because of the importance of the local, microscale, interactions between the microvessel and the ECM, the model will emphasize these aspects. In addition to establishing a better understanding of the relationship between angiogenic vessels, the surrounding ECM structure, and the mechanics of the tissue undergoing angiogenesis, the project will provide the basis for improved control of tissue vascularization in both native tissues (e.g., repairing ischemic tissue) and tissue engineered constructs. PUBLIC HEALTH RELEVANCE: The proposed research will elucidate fundamental aspects of the roles of mechanical forces and extracellular matrix structure in angiogenesis. The process of angiogenesis is an integral feature of wound healing and tumor metastastis. The results of this research will provide a mechanistic understanding of the interaction of angiogenic microvessels with the extracellular matrix, and provide guidelines for the design and development of vascularized tissue replacements.